Wire grip terminal

ABSTRACT

A wire grip circuit board eyelet with wire-engaging burrs on the edges of the wire grip fingers and the method of making the same.

United States Patentf Assignee Int.

Weldon L. Brublker Mechanicsburg, Pa. 851,030

Aug. 18, 1969 Aug. 24, 1971 Berg Electronics, Inc. Nee Cumberhnd, Pa.

Inventor Appl. No. Filed Patented WIRE GRIP TERMINAL 3 Claims, 8 DrawingFigs.

US. ("I 339/258 R, 339/95 R, 339/275 R H0]: 13/12 50 Field ofSearch [56]Referencr: Citeql UNITED STATES PATENTS 3,000,402 10/1962 Olsson m1.339/242 3,510,831 5/1910 De vim 339/258 Primary Exeiminer-Joseph H.McGlynn AuorneyThoma Hooker ABSTRACT: A wire grip circuit board eyeletwith wire-engaging burrs on the edges of the wire grip fingers and themethod of making the same.

WIRE GRIP'TERMINAL 1 This invention relates to wire grip terminals andin particular to wire grip circuit board eyelets and the method ofmaking the same. Wire grip fingersin the terminals are provided withwire-engaging burrs on the edges thereof so that when a lead wire isinserted into a terminal, the burrs bite into the wire and hold itrelative to the terminal. The burrs are formed by punching the wire gripfingers out of one side of metal'stock and then bending the fingers backthrough the thickness of the stock into the interior of the terminal.

Circuit board eyelets of the type disclosed in U.S. Pat. Nos. 3,368,188and 3,504,328, both assigned to Berg Electronics, Inc., utilize wiregrip fingers to hold' a lead wire fixed relative to the eyelet prior toand during soldering. Other terminals, such as those disclosed in U.S.'Pat. "No. 3,283,288 also use wire grip fingers for holding a leadprior to and during soldermg. I

In some terminals using wire grip fingers it has been foundFIG;laboringpunchingofthefingers from the strip, sharp Burrs adjacentedges 18 are also formed on st'rip1l2 The burrs 22' extend along thesheared edges of each finger'and burrs '22 are formedon the fingersatedges 18' facing strip "12 I around the finger from one end of thestrip connecting portion" desirable to increase the gripping ability ofthe fingers so that leads inserted into the terminals are more'tig'htly'held against shifting within the terminal; This isparticularly true in the case of circuit board eyelets of the typereferred to where the eyelets are very small in size and are used toholdleads supporting relatively heavy circuit components. The weight ofthe components tends to shifi the leads in the eyelet, with the resultthat the leads may project beneath the bottom of thecircuit board,thereby requiring clipping following soldering. Ad ditionally, the leadsmay even be pulled out of the eyelets so as to require reinsertionprior'to soldering. The invention improves the wire gripping capacity ofcircuit board eyelets and other terminals using wire grip fingers byproviding sharp leadengaging burrs on the edges of the fingers facingthe interior of the terminal. When a lead is inserted into the terminalthe fingers are forced apart and the burrs bite into the lead to providean improved grip on the'lead. I a i The wire gripburrs are formed by amanufacturing process in which the wire grip fingers are punched fromthe stock forming the eyelet so that burrs are fonned on the edges ofthe fingers adjacent the stock. The fingers are then pushed back intothe finger cutouts in the stock and the stock is rolled to form the bodyof the eyelet with the burrs on the fingers facing the interior of theeyelet. After rolling of the eyelet, the fingers are bent into theeyelet with the ends of the fingers positioned together within theeyelet. The burrs face the interiorof the eyelet so that they engageleads inserted into the eyelet with improved wire gripping ability.

Other objects and features of the invention will become ap- 20 to theother end of the-portion. The edgesZS of the fingers I facing awayfrom-strip 12 are punching operation.

rounded somewhat during the I ollowing indexing ofstrip ll-i' to thesecond station of the progressive die, the '16 are moved back into thethickness of strip 12 as illustrated in'FIG'. 3. It is necessary .toposition the fingers within' the strip so that the eyelet may be rolledwithout collapsing the body portion. Movement of the fingers back intothe strip does not materially dull the burrs 22". At thesecond stationstrip 12 is partially blanked to define the P rtion from whic l 11 W 1will hemmed At the third statimiQblanking ofthe strip-is completed isform eyelet preform 26L Slits 28 are formedirr the top of the preformand the top of the preform is slightly flared. Notches 30. areiform'edon the bottom of the preform. I v

A At thefourth station, preform 26 is offset relative to carrier strip32 the ends 34 of the preform are rolled slightly asIiI- lustrated inFIG. 4. The preforr'n'is rolled a direction so that the burrs 22 onfingers: 16 will face the interior of the further tothe' configurationillustrated' in FIG. '5. I

I At the sisthstation, rolling of the preform is'completed 'so that ends34 abut each other at seam 36 and t h'e portion of the preformcontaining fingers is cylindrical. At the sixth station, as illustratedin FIG. 6, fingers l6remain located within the thickness of the preform2G and burrs 22 on the fingers face the interior of the rolled preform.

Thefonnatio'n of eyelet '10 is completed at the seventh'sta tion wherefingers 16 are bent into 1thefinterior-of the eyeletbody so that,illustrated in FIG. 7, the freeends 38 of the completed eyelet. At thestation the preform 26 is rolled:

' fingers are grouped together. At. this time the portions of the eyeeuo between notches 30 may be bent inwardly toiprovide a roundedlead-in) to facilitate positioning of the eyelet within acircuitboar'dhole.

' As illustrated in FIG. 8 a circuit boardeyeletfl l o may be I severedfrom strip 32 and seated within 'holefQZ of circuit board 44, withlead-in 40 flared outwardly to secure'thee'ye'let within the hole. Uponinsertion of a lead wire, 46' within the eyelet, fingers 16 are spreadapart so that burrs 2:2 engage the parent as the description proceeds,especially when taken in conjunction with the accompanying drawingsillustrating a preferred embodiment of the invention, wherein:-

FIG. I is a perspective view of the progression of a metal strip througha progressive die illustrating the formation of a circuit board eyeletaccording to the invention;

FIGS. 2, 3, 4, 5, 6 and 7 are sectional views takenrespectively alonglines 22, 3-3, 4-4, 5 5, 6-6, and 77 of FICLI; and I FIG. 8 is asectional view illustrating the use of a board eyelet according to theinvention.

As illustrated in FIG. 1, circuit board eyelet circuit 10 formed wire.Movement ofthe wire past the'burrs causes the burrs to bite intothe wireso that the fingers grip thewire securely.,The burrs at the long edge 18of the fingers are urged into'contact with a lead inserted into'eyelet-10 and form a" locking grip on the lead'which'resists removal of thelead from the-eyelet. This is because the burrs cross the surface of thelead at an'acute angle. The burrs'at the free ends of the fingers alsoengage the lead.

In the manufacture of a conventional wire grip terminals,

" the fingers are punched from the stock in a' direction opposite from astrip of relatively thin sheet metal stock l2 which is 1 moved past anumber of die stations. At each station a the pair performs an operationon the strip. The strip 12 may be made of brass suitably coated withsolder or other metal. The strip is provided at regular intervals withpilot holes 14 which run the length of the strip and are used to assureproper orientation of the strip at each die station. The strip is'movedin the direction ofthe arrow in FIG. 1.

the direction in which fingers 16 are punched at the first posi- I tionof the progression illustrated in FIGS. 1 and 2 so that the wire gripfingers onthe completed terminal are not provided with wireorlead-engaging burrs facing into the body of the. terminal. Rather, theedges of the fingers facing the interioi of the terminalare rounded anddo not bite into'the lead.

While I have'illustrated and described a preferfed .embediment ofrny'invention, it is understood that' t hi's is eapable of modification,and I therefore do not wish to belimited'to the Precise details setfans. Y

WhatIclairjnas my invention is: I I I l. A 'wire grip terminalcomprising a longitudinal hollow body,'at least one wire grip finger cutfrom the wall of said body and projecting into theinterior of said'body, and a con- I tinuous wire grip b'urr on the corner of the fingerfacing the in- At the first station of the progressive die, fourtriangularly 4 shaped wire grip fingers 16 are punched from the. strip12. Each finger is severed from the strip along the edges '18 and teriorof the body extending from the junction of one side of the finger withthe wall alongsaid side of the finger, past the tip of the finger andalong the other side of the finger to the remains attached to the stripat connecting portion 20. The junction of said other side of the fingerandthe wall.

7 together, a continuous burr extending fromthe wallalong both edges onsaid sides of the finger and around the apex of the finger.

3. A circuit board eyelet formed from relatively thin sheet metal stockcomprising an elongate cylindrical hollow body rolled from said-stock,means at the ends of said body .for confining theeyelet within a circuitboard hole, and a plurality of tapered wire grip fingers cut out fromsaid body and bent into n the interior of said body with the ends ofsaid fingers grouped together, and a burr extending from the wall alongeach side of each finger at the edge facing the interior of the body forengaging a lead inserted into said eyelet.

1. A wire grip terminal comprising a longitudinal hollow body, at leastone wire grip finger cut from the wall of said body and projecting intothe interior of said body, and a continuous wire grip burr on the cornerof the finger facing the interior of the body extending from thejunction of one side of the finger with the wall along said side of thefinger, past the tip of the finger and along the other side of thefinger to the junction of said other side of the finger and the wall. 2.A wire grip terminal as in claim 1 including means for attaching saidbody to a circuit board, and a plurality of tapered wire grip fingerscut out from said body and bent into the interior of the body with theends of said fingers grouped together, a continuous burr extending fromthe wall along both edges on said sides of the finger and around theapex of the finger.
 3. A circuit board eyelet formed from relativelythin sheet metal stock comprising an elongate cylindrical hollow bodyrolled from said stock, means at the ends of said body for confining theeyelet within a circuit board hole, and a plurality of tapered wire gripfingers cut out from said body and bent into the interior of said bodywith the ends of said fingers grouped together, and a burr extendingfrom the wall along each side of each finger at the edge facing theinterior of the body for engaging a lead inserted into said eyelet.